Still another objection is implied in Dr. Sapir’s own statement of the case. It is not necessary for the natives to look at the levirate from the point of view hitherto assumed. Instead of defining the paternal uncle in terms of his potential fatherhood, they may have a word distinct from that for father to designate the step-father and the paternal uncle. Dr. Sapir cites the Upper Chinook by way of illustration. In other words, the action of the levirate is equivocal. It may affect nomenclature so as to produce the semblance of the Dakota principle, but it may also produce quite different results. It may also fail to affect terminology at all, as apparently is the case in Semitic languages with their descriptive nomenclature. In this connection a qualification must be made that applies equally to the exogamy hypothesis. Though the ultimate cause of a terminological feature be the levirate, the immediate cause in a given instance may well be an historico-geographical one. If the Chinook nomenclature is differently affected by the levirate from that of the Yahi, the proximate reason may be simply the fact that the Chinook did not come into contact with the same peoples as the Yahi and thus had no chance to borrow their nomenclature. In other words, admitting an influence of the levirate, it is not necessary to assume that it has repeatedly produced the same terminological effects independently. I know of at least one instance in which the hypothesis advanced by Dr. Sapir seems definitely excluded, leaving exogamy in the field as the efficient cause. The Hopi system conforms to the essentials of the Dakota type, but neither the levirate nor the marriage with two sisters is in vogue. It cannot be argued that the Dakota features were borrowed from some other Southwestern tribe possessing these usages, first, because the Dakota features are far more highly developed among the Hopi than among other Pueblo Indians; secondly, because it is very doubtful whether the practices in question occur among other Pueblo tribes.[48] In justice to Dr. Sapir it must be pointed out that he does not advance his hypothesis as a general interpretation of the phenomena. As he suggests, it is most serviceable where the exogamous factor does not occur, or, as I should add, where diffusion of features from a system affected by exogamy seems improbable. I have examined his hypothesis as if it were designed to account for all the relevant phenomena simply in order to bring out clearly its inferiority from this point of view to the theory of exogamy.